BoSoxFan is right on with his points. About 18 years ago, our family went on a vacation package to Hawaii via UA. Joined the Mileage Plus program at the airport, but when I sent our ticket receipts in to get credit, I received the reply that since they were "industry discounted" no FF mileage would be given. (The airfare was over $800 back in 1983). So I said to myself, BYE BYE United, haven't flown with them since and that was about 1.5 million base miles ago. Something tells me it would have been better for UA to give the mileage credit back in 1983 for that family trip to Hawaii.